Golf club head

ABSTRACT

A golf club head according to the present invention is provided with a head body having a crown portion and a sole portion, and having an opening surrounded by the crown portion and the sole portion, and a face member closing the opening of the head body, the face member being formed in a cup shape having a planar face portion and a peripheral portion extending from a periphery of the face portion, the peripheral portion having a thick portion joined to an end face of the opening of the head body, and a connecting portion connecting the thick portion and the face portion, and, in the connecting portion, a thickness of a portion connected to the thick portion being thinner than the thick portion.

TECHNICAL FIELD

The present invention relates to a golf club head.

BACKGROUND ART

Wood-type golf club heads have undergone many refinements heretofore,and various proposals have been made in order to extend the carrydistance. For example, as shown in JP 2007-54198A, some wood-type golfclub heads employ a face member having a so-called cup face structure.Specifically, the golf club head is constituted by a head body in whichan opening is formed, and a face member that closes the opening in thehead body, and the face member is formed in a cup shape having a planarface portion and a peripheral portion extending from the periphery ofthe face portion. The golf club head is formed, by joining theperipheral portion of the face member and the opening periphery of thehead body by welding. With such a cup face structure, the welded portionof the face member and the head body will be away from the periphery ofthe face portion on the back side of the head. Thus, it is possible tolower the rigidity of the face portion, in comparison with a golf clubhead in which the face member is planar, and consequently the advantageof high rebound performance is obtained.

JP 2007-54198A is an example of related art.

Incidentally, with the cup face structure, rigidity increases andrebound performance decreases when the peripheral portion of the facemember has a large thickness, and thus the peripheral portion ispreferably thin. However, when the peripheral portion is made thinner,there is a risk that welding defects will occur during the welding,resulting in holes opening up in the peripheral portion or largedeformations occurring. The present invention has been made in order tosolve the above problem, and an object thereof is to provide a golf clubhead that is able to prevent welding defects, while improving reboundperformance.

SUMMARY OF THE INVENTION

A golf club head according to the present invention includes a head bodyhaving a crown portion and a sole portion, and having an openingsurrounded by the crown portion and the sole portion, and a face memberclosing the opening of the head body, the face member being formed in acup shape having a planar face portion and a peripheral portionextending from a periphery of the face portion, the peripheral portionhaving a thick portion configured to join to an end face of the openingof the head body, and a connecting portion connecting the thick portionand the face portion, and the connecting portion including a thinportion whose thickness is thinner than the thick portion.

In the golf club head, a configuration can be adopted in which at leastpart of the connecting portion has a base end portion connecting thethin portion and the face portion, and a thickness of the base endportion is smaller than the thickness of the thick portion.

In the golf club head, a configuration can be adopted in which at leastpart of the connecting portion has a base end portion connecting thethin portion and the face portion, and a thickness of the base endportion is larger than the thickness of the thick portion.

In the golf club head, a configuration can be adopted in which thethickness of the base end portion is larger than the thickness of thethin portion.

In the golf club head, the base end portion can be formed in a range of20 mm from a face center in a toe-heel direction.

In the golf club head, the connecting portion can further include,between the thick portion and the thin portion, a transition portionwhose thickness becomes incrementally thinner proceeding toward the thinportion from the thick portion.

In the golf club head, a length of the connecting portion in a face-backdirection can be constituted to be longer than a length of the thickportion in the face-back direction.

In the golf club head, a length of the peripheral portion in theface-back direction can be set to greater than or equal to 18 mm.

With the golf club head according to the present invention, weldingdefects can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a golf club head according to anembodiment.

FIG. 2 is a plan view of the golf club head of FIG. 1 in a referencestate.

FIG. 3 is cross-sectional view along line A-A in FIG. 2.

FIG. 4A is a diagram illustrating a boundary of a face portion.

FIG. 4B is a diagram illustrating the boundary of the face portion.

FIG. 5 is an exploded perspective view of the head.

FIG. 6 is a partially enlarged view of FIG. 3.

FIG. 7 is a cross-sectional view showing another example of FIG. 6.

FIG. 8 is a cross-sectional view showing another example of FIG. 6.

FIG. 9 is a cross-sectional view showing another example of FIG. 6.

FIG. 10 is a plan view of the golf club head of FIG. 1 in the referencestate for describing a center range.

EMBODIMENTS OF THE INVENTION

Hereinafter, an embodiment of a golf club head according to the presentinvention will be described, with reference to the drawings.

1. Overview of Golf Club Head

FIG. 1 is a perspective view of this golf club head, FIG. 2 is a planview of the head in a reference state, and FIG. 3 is a cross-sectionalview along line A-A in FIG. 2. As shown in FIGS. 1 to 3, this golf clubhead (hereinafter, may be referred to simply as “head”) 100 is awood-type golf club head having a hollow structure with an internalspace, and a wall surface is formed by a face portion 1, a crown portion2, a sole portion 3 and a hosel portion 4. Specifically, the presentinvention can be applied to golf club heads such as drivers, utilities(hybrids), and fairway woods.

The face portion 1 has a face surface that is the surface that hits theball, and the crown portion 2 adjoins the face portion 1 and constitutesthe upper surface of the head 100. The sole portion 3 mainly constitutesthe bottom surface of the head 100, and constitutes the outer peripheralsurface of the head 100 other than the face portion 1 and the crownportion 2. That is, in addition to the bottom surface of the head 100,the region extending from the toe side of the face portion 1 around theback side of the head to the heel side of the face portion 1 is alsopart of the sole portion 3. As shown in FIG. 3, in the presentembodiment, a recessed portion 31 for attaching a weight member(illustration omitted) is formed in the sole portion 3. Furthermore, thehosel portion 4 is a region that is provided adjoining the heel side ofthe crown portion 2, and has an insertion hole 41 into which a shaft(illustration omitted) of the golf club is inserted, and that is formedin a cylindrical shape extending inside the head. A center axis line Zof this insertion hole 41 coincides with the axis line of the shaft.

Here, the reference state when setting the golf club head 100 on theground will be described. First, as shown in FIG. 2, a state where theabove center axis line Z is contained in a plane P1 that isperpendicular to the ground and the head is placed on the ground at apredetermined lie angle and real loft angle is prescribed as thereference state. The plane P1 will be referred to as a referenceperpendicular plane. Also, as shown in FIG. 2, the direction of the lineof intersection between the reference perpendicular plane P1 and theground will be referred to as a toe-heel direction, and the directionthat is perpendicular to this toe-heel direction and parallel to theground will be referred to as a face-back direction. Also, the directionthat is orthogonal to the toe-heel direction and the face-back directionmay be referred to as an up-down direction.

In the present embodiment, the boundary between the face portion 1 andthe crown portion 2 and between the face portion 1 and the sole portion3 can be defined as follows. That is, in the case where a ridgeline isformed therebetween, this ridgeline will be the boundary. On the otherhand, in the case where a clear ridgeline is not formed, then in each ofcross-sections E1, E2, E3 and so forth that contain a straight line Nconnecting a head center of gravity G and a sweet spot SS, as shown inFIG. 4A, a position Pe at which a curvature radius r of a contour lineLf of the face outer surface first reaches 200 mm in a direction towardthe outer side of the face from the sweet spot side, as shown in FIG.4B, will be the periphery of the face portion 1, and this periphery isdefined as the boundary with the crown portion 2 or the sole portion 3.Note that the sweet spot SS is the point of intersection between thenormal (straight line N) of the face surface that passes through thehead center of gravity G and this face surface.

Also, in the present embodiment, the boundary between the crown portion2 and the sole portion 3 can be defined as follows. That is, in the casewhere a ridgeline is formed between the crown portion 2 and the soleportion 3, this ridgeline will be the boundary. On the other hand, inthe case where a clear ridgeline is not formed therebetween, the contourwhen the head is set in the reference state and viewed from directlyabove the center of gravity of the head 100 will be the boundary.

The head 100 can, for example, be formed with a titanium alloy(Ti-6Al-4V, Ti-8Al-1Mo-1V, etc.) having a specific gravity ofsubstantially about 4.3 to 4.5. Apart from a titanium alloy, the headcan also be formed using one or two or more materials selected fromstainless steel, maraging steel, an aluminum alloy, a magnesium alloyand an amorphous alloy, for example.

The volume of this golf club head 100 is desirably from 90 cm³ to 470cm³ inclusive, for example.

2. Assembly Structure of Golf Club Head

The golf club head 100 according to the present embodiment isconstituted, as shown in FIG. 5, by assembling a head main body 101having a crown portion 2 and a sole portion 3 and a cup-shaped facemember 102 having a face portion 1 and a peripheral portion 15 extendingfrom the periphery of the face portion 1. This head main body 101 has anopening 18 surrounded by the crown portion 2 and the sole portion 3, andthe face member 102 is attached so as to close this opening 18. That is,the end face of the peripheral portion 15 of the face member 102 isbutted against the end face of the opening 18 of the head main body 101,and these portions are joined by welding (so-called cup face structure).The face member 102 is integrated with the head main body 101, by beingattached to an edge portion of the opening 18 of the head main body 101,and the peripheral portion 15 of the face member 102 thereby functionsas part of the crown portion 2 and the sole portion 3 of the head 100.

Accordingly, the surface that is integrally formed as a result of theperipheral portion 15 of the face member 102 being attached to the headmain body 101 constitutes the crown portion 2 and the sole portion 3 ofthe head 100. Thus, strictly speaking, the crown portion 2 and the soleportion 3 of the head main body 101 are part of the crown portion 2 andthe sole portion 3 of the head 100, although, in this specification,these portions of the head main body 101 may also be referred to simplyas the crown portion 2 and the sole portion 3, without making thisdistinction.

Note that the cross-section of FIG. 3 is a cross-section in theface-back direction passing through a face center. Hereinafter, theplane prescribing this cross-section will be referred to as a centerreference plane. The face center can be defined as follows. First, anarbitrary point Po is determined generally in a vicinity of the centerof the face portion 1 (face surface) in the toe-heel direction and theup-down direction. A line x extending in the toe-heel direction is drawnthrough this point Po, and a midpoint Px of this line x is determined.Next, on the face portion 1, a line y extending in the up-down directionis drawn through the point Px, and a midpoint Py of this line isdetermined. A process of redrawing the line extending in the toe-heeldirection through the point Py determined in this way as the line x andthereinafter redetermining the point Py in a similar manner to thatdescribed above is then repeatedly performed. A new point Py at whichthe distance between the previous point Py and the new point Py becomes0.5 mm or less during repetition of this process is defined as the facecenter. Note that, more specifically, the above line x passing throughthe point Po is the line of intersection between the face surface(surface of the face portion 1) and a plane that contains the normal ofthe face surface passing through this point Po and is parallel to thetoe-heel direction. Also, more specifically, the above line y passingthrough the point Px is the line of intersection between the facesurface and a plane that contains the normal of the face surface passingthrough this point Px and is parallel to the up-down direction. Also,more specifically, the above line x passing through the point Py is theline of intersection between the face surface and a plane that containsthe normal of the face surface passing through this point Py and isparallel to the toe-heel direction. Note that the lengths of the abovelines x and y are measured along the face surface.

3. Structure in Vicinity of Peripheral Portion of Face Member

Next, the structure of the peripheral portion 15 of the face member 102will be described, with reference also to FIG. 6. FIG. 6 is a partiallyenlarged view of the face member in the vicinity of the crown portion inFIG. 3. As shown in this diagram, a thick portion 151 is formed in theback-side end portion of the peripheral portion 15, or in other words,the end portion joined to the crown portion 2. The face-side end portionof this thick portion 151 has a transition portion 152 whose thicknessincrementally decreases proceeding toward the face side, and theface-side end portion of this transition portion 152 is connected to theface portion 1 by a thin portion 153. The thickness of the thin portion153 is the same as the thickness of the face-side end portion of thetransition portion 152, generally throughout an entirety thereof.

A thickness t1 of the thick portion 151 can, for example, be set from0.8 to 1.5 mm, and is preferably from 1.0 to 1.4 mm. Also, a thicknesst2 of the thin portion 153 need only be thinner than the thick portion151, and can, for example, be set from 0.4 to 1.4 mm, and is preferablyfrom 0.6 to 1.0 mm. For example, the thickness t1 of the thick portion151 can be set to 1.2 mm and the thickness t2 of the thin portion 153can be set to 0.7 mm.

A length d1 of the thick portion 151 in the face-back direction can, forexample, be set from 1 to 5 mm. This length d1 is a length prescribed onthe abovementioned center reference plane with the head 100 in thereference state, and is the length on the inner wall surface side of thethick portion 151. Note that the length d1 of the thick portion 151 inthe face-back direction is shorter than the total length of thetransition portion 152 and the thin portion 153 in the face-backdirection. An increase in the weight of the peripheral portion 15 canthereby be suppressed. Note that in the case where the thickness t1 ofthe thick portion 151 is measured at multiple points, the smallestmeasurement value of those measured is taken as the thickness t1. Themeasurement method is also generally the same for the thickness t2, andin the case where the thickness t2 is measured at multiple points, thesmallest measurement value of those measured is taken as the thicknesst2.

Also, a length d2 of the peripheral portion 15 in the face-backdirection is, for example, preferably greater than or equal to 5 mm,more preferably greater than or equal to 15 mm, particularly preferablygreater than or equal to 18 mm, and most preferably greater than orequal to 22 mm. On the other hand, although not particularly limited,the upper limit of the length d2 is preferably less than or equal 28 mm,and more preferably less than or equal to 26 mm. Here, the length d2 isa length prescribed on the center reference plane with the head 100 inthe reference state, and is taken as the length from the boundary (e.g.,ridgeline) between the face portion 1 and the peripheral portion 15 tothe end portion of the outer surface of the thick portion 151.

Note that the thick portion 151, the transition portion 152 and the thinportion 153 are formed to span the entire circumference of theperipheral portion 15 including not only the crown portion 2 side butalso the sole portion 3 side.

As shown in FIG. 6, a thick portion 51 is also formed in the end portionon the head body 101 side that is joined to the thick portion 151, thatis, on the periphery of the opening 18. The thickness of this thickportion 51 and a length d3 in the face-back direction can be configuredto be the same as the thick portion 151 of the peripheral portion 15,including the measurement method. Note that an end face 159 on the backside of the thick portion 151 of the peripheral portion 15 and an endface 52 on the face side of the thick portion 51 of the head body 101extend generally parallel to the face portion 1 in the reference state.

4. Manufacturing Method of Golf Club Head

Next, an example of the manufacturing method of the above golf club headwill be described. First, the abovementioned head main body 101 and facemember 102 are prepared. Such a head main body 101 and face member 102can be produced with various methods. For example, the head main body101 can be manufactured by casting such as a well-known lost waxprecision casting process. Also, the face member 102 can be manufacturedby a method such as forging, plate pressing or casting, for example.Also, in the case of forming the face member 102 using a rolledmaterial, the pre-processing plate of the face member 102 is processedsuch that the rolling direction substantially coincides with thedirection from an upper portion on the toe side of the face portion 1 toa lower portion on the heel side.

The golf club head 100 is then completed when predetermined coating isperformed after joining these portions by welding (TIG (tungsten inertgas) welding, plasma welding, laser welding, brazing, etc.), forexample.

5. Features

According to the above embodiment, the following effects can beobtained.

(1) An advantage of a cup face structure such as the above is that therebound performance of the head increases, but when the peripheralportion 15 has a large thickness, the rigidity thereof increases, andthere is a risk that an improvement in the rebound performance willconversely not be readily achieved. However, when the thickness of theperipheral portion 15 is reduced, there is a risk that welding defectswill occur when welding the peripheral portion 15 to the end face of theopening 18 of the head body 101, resulting in holes opening up in theperipheral portion 15 or the peripheral portion 15 being greatlydeformed. In view of this, in the present embodiment, a thick portion151 having a large thickness is formed in the back-side end portion ofthe peripheral portion 15, and the heat capacity is increased. Thus,welding defects can be prevented from occurring. Also, since thethickness of the thin portion 153 between the thick portion 151 and theface portion 1 is thinner than the thick portion 151, an increase in therigidity of the peripheral portion 15 can be suppressed. The reboundperformance of the head can thereby be improved.

(2) A transition portion 152 whose thickness incrementally decreases isformed between the thick portion 151 and the thin portion 153. Forexample, when the thick portion 151 and the thin portion 153 aredirectly connected without providing the transition portion 152, a sharpstep is formed therebetween. When such a step is formed, stress isconcentrated when the ball is hit, and there is a risk that damage suchas cracking will occur. In view of this, in the present embodiment,concentration of stress is suppressed by providing the transitionportion 152.

(3) The inventors of the instant invention discovered through diligentresearch that a place (e.g., about 15 mm) on the crown portion that isat a predetermined distance from the face portion 1 flexes the mostreadily when the ball is hit, depending also on the type of club. Whenthe joining portion of the head body 101 and the peripheral portion 15is located near this place, there is a risk that the rebound performancewill be affected, since the joining portion has a large thickness. Assuch, when the length d2 of the peripheral portion 15 is, as describedabove, greater than or equal to 5 mm and less than 12 mm or greater thanor equal to 18 mm less than 22 mm, for example, the joining place willbe provided so as to avoid the part that flexes the most readily, and adecrease in rebound performance can be suppressed. In particular, whenthe length d2 is greater than or equal to 18 mm, the length of theperipheral portion becomes even longer, and rebound performanceincreases further. In this case, having a thick portion 151 and a thinportion 153 such as in the present embodiment is particularlyadvantageous.

Note that, in the present embodiment, the connecting portion of thepresent invention is constituted by the transition portion 152 and thethin portion 153.

6. Variations

Although an embodiment of the present invention has been describedabove, the present invention is not limited to the above embodiment, andvarious modifications can be made without departing from the spirit ofthe invention. Also, the following variations can be combined asappropriate. For example, the following modifications can be made.

6-1. The mode of the peripheral portion 15 is not limited to the aboveembodiment, and need only at least have the thick portion 151, and beprovided with the thin portion 153 having a smaller thickness than thethick portion 151 between the thick portion 151 and the face portion 1.For example, in the example shown in FIG. 7, the portion between theface portion 1 and the thick portion 151 in the peripheral portion 15 isconstituted by a base end portion 154, the thin portion 153, and thetransition portion 152 that are aligned in the face-back direction.Here, a thickness t4 of the base end portion 154 is thicker than athickness t3 of the thin portion 153, and thinner than the thickness t1of the thick portion 151. The thickness t4 of the base end portion 154is, as shown in FIG. 7, measured at a position approximately 3 mm to theback side in the face-back direction from the abovementioned boundaryPe. For example, the thicknesses of the thick portion 151, the thinportion 153 and the base end portion 154 can be set to 1.2 mm, 0.7 mmand 0.9 mm, respectively. Note that, in this mode, the connectingportion of the present invention is constituted by the base end portion154, the thin portion 153 and the transition portion 152.

Also, as shown in FIG. 8, the thickness of the base end portion 154 canbe constituted to be larger than the thick portion 151. For example, thethicknesses of the thick portion 151, the thin portion 153 and the baseend portion 154 can be set to 1.2 mm, 0.7 mm and 1.4 mm, respectively.

Alternatively, as shown in FIG. 9, the thickness can also be increased,such that the connecting portion of the face portion 1 and theperipheral portion 15, or in other words, the cross-section of the baseend portion 154, will be triangular.

In the above example, a portion having a large thickness (e.g., the baseend portion 154) is provided in part of the connecting portion accordingto the present invention, but the place and position thereof is notparticularly limited. The connecting portion of the present inventioncan also be formed such that the thickness of a region other than thethin portion 153 at least partially increases or decreasesincrementally. That is, various modes are possible with theconfiguration of the connecting portion according to the presentinvention, and the thin portion 153 need only be formed in at least partof the entire circumference of the peripheral portion 15.

The transition portion 152 is not necessarily required, and, forexample, the thick portion 151 and the thin portion 153 can also bedirectly connected. Alternatively, a region having a larger thicknessthan the thin portion 153 and being substantially uniform in theface-back direction can also be provided between the thick portion 151and the thin portion 153. In suppressing stress concentration such asdescribed above, however, the transition portion 152 is preferablyprovided. The transition portion 152 can also be provided in part of theentire circumference of the peripheral portion.

6-2. The abovementioned modes of the peripheral portion 15 can also becombined. For example, the cross-sectional shape of the peripheralportion 15 can be constituted as shown in FIGS. 7 to 9, in the vicinityof the face center in the toe-heel direction, for example, such that therebound performance does not become too high in the vicinity of the facecenter in the toe-heel direction. In other words, rather than providingthe thin portion 153 around the entire circumference of the peripheralportion 15, the thickness can be increased in part (e.g., a portion ofequivalent thickness to the thick portion 151 or a portion such as thebase end portion 154), and the rebound performance can thereby bereduced. As the range in which such a cross-sectional shape is adopted,a range (hereinafter, center range) between a place 20 mm to the toeside and a place 20 mm to the heel side from the face center can beadopted, such as shown in FIG. 10, for example. On the other hand, theremaining range, or in other words, the range to the toe side and theheel side from the center range, can be formed with a cross-sectionalshape having a thin portion 153 such as shown in FIG. 6. The reboundperformance can thereby be improved other than in the center range.

Note that a center range in which the thickness is increased can beprovided on at least one of the crown portion 2 side and the soleportion 3 side of the peripheral portion 15. Also, the length of thethick portion 151 in the face-back direction is not particularlylimited, and, as in the above embodiment, the length of the thickportion 151 in the face-back direction can, in addition to being madeshorter than the connecting portion (at least 153 out of 152, 153, 154),also be made longer than or equivalent to the connecting portion.

6-3. The shapes of the crown portion 2 and the sole portion 3 are notparticularly limited, and various recesses and protrusions can beprovided, from the viewpoint of design and structure. For example, inthe above embodiment, a recessed portion 31 for attaching a weightmember is provided, but this is an example of the shape of the soleportion 3, and the recessed portion 31 need not be provided.

LIST OF REFERENCE NUMERALS

-   -   1 Face portion    -   15 Peripheral portion    -   151 Thick portion    -   152 Transition portion    -   153 Thin portion (portion connected to thick portion)    -   154 Base end portion    -   2 Crown portion    -   3 Sole portion    -   4 Hosel portion    -   101 Head body    -   102 Face member

What is claimed is:
 1. A golf club head comprising: a head body having acrown portion and a sole portion, and having an opening surrounded bythe crown portion and the sole portion; and a face member closing theopening of the head body, wherein the face member is formed in a cupshape having a planar face portion and a peripheral portion extendingfrom a periphery of the face portion, the peripheral portion has: athick portion configured to join to an end face of the opening of thehead body; and a connecting portion connecting the thick portion and theface portion, and the connecting portion includes a thin portion whosethickness is thinner than the thick portion.
 2. The golf club headaccording to claim 1, wherein at least part of the connecting portionhas a base end portion connecting the thin portion and the face portion,and a thickness of the base end portion is smaller than the thickness ofthe thick portion.
 3. The golf club head according to claim 1, whereinat least part of the connecting portion has a base end portionconnecting the thin portion and the face portion, and a thickness of thebase end portion is larger than the thickness of the thick portion. 4.The golf club head according to claim 2, wherein the thickness of thebase end portion is larger than the thickness of the thin portion. 5.The golf club head according to claim 4, wherein the base end portion isformed in a range of 20 mm from a face center in a toe-heel direction.6. The golf club head according to claim 3, wherein the thickness of thebase end portion is larger than the thickness of the thin portion. 7.The golf club head according to claim 6, wherein the base end portion isformed in a range of 20 mm from a face center in a toe-heel direction.8. The golf club head according to claim 1, wherein the connectingportion further includes, between the thick portion and the thinportion, a transition portion whose thickness becomes incrementallythinner proceeding toward the thin portion from the thick portion. 9.The golf club head according to claim 1, wherein a length of theconnecting portion in a face-back direction is longer than a length ofthe thick portion in the face-back direction.
 10. The golf club headaccording to claim 1, wherein a length of the peripheral portion in theface-back direction is greater than or equal to 18 mm.